Sugammadex (Trade name: Bridion) is first disclosed in U.S. Pat. No. 6,670,340 assigned to Akzo Nobel. Sugammadex sodium was approved in EMEA as an agent for reversal of neuromuscular blockade by the agent rocuronium in general anaesthesia in 2008 and is the first selective relaxant binding agent (SRBA).

Sugammadex sodium contains 8 recurring glucose units each with 5 asymmetric carbon atoms, in total 40 asymmetric carbon atoms for the whole molecule. Sugammadex is a modified γ-cyclodextrin, with a lipophilic core and a hydrophilic periphery. The gamma cyclodextrin has been modified from its natural state by placing eight carboxyl thio ether groups at the sixth carbon positions.
The U.S. Pat. No. 6,670,340 assigned to Akzo Nobel discloses a process for preparing Sugammadex sodium as depicted in Scheme-I:

The first step in the process in the scheme-I involves the preparation of Vilsmeier Hack reagent by the reaction of DMF, triphenylphosphine and Iodine. The triphenylphosphine oxide is formed as a byproduct of the first step. Removal of triphenylphosphine oxide from the product is very difficult from the reaction mass as it requires repeated washing with DMF under argon atmosphere, which leads to inconsistency in yield of final product Sugammadex.
The second step involves the reaction of 6-perdeoxy-6-per-Iodo-Gamma cyclodextrin with 3-mercapto propionic acid in presence of alkali metal hydrides in an organic solvent to give 6-per-deoxy-6-per-(2-carboxyethyl)thio-γ-cyclodextrin sodium salt.
The PCT publication WO2012/025937 discloses preparation of Sugammadex involving the reaction of gamma cyclodextrin with phosphorous halide in presence of organic solvent, thereby overcomes the formation of triphenyl phosphine oxide. The publication also discloses the use of 6-per deoxy-6-per-chloro-γ-cyclodextrin in the preparation of the Sugammadex.
The purification techniques in the prior arts employ column chromatographic/membrane dialysis techniques which are costly and not convenient in large scale operations.
Therefore, there exists a need for an improved and economically efficient process for the preparation of Sugammadex sodium.